scholarly journals Structural Effects in the Iridium Complex Series: Photoredox Catalysis and Photoinitiation of Polymerization Reactions under Visible Lights

2017 ◽  
Vol 218 (18) ◽  
pp. 1700192 ◽  
Author(s):  
Mohamad-Ali Tehfe ◽  
Marc Lepeltier ◽  
Frédéric Dumur ◽  
Didier Gigmes ◽  
Jean-Pierre Fouassier ◽  
...  
2015 ◽  
Vol 6 (4) ◽  
pp. 613-624 ◽  
Author(s):  
Sofia Telitel ◽  
Frederic Dumur ◽  
Siham Telitel ◽  
Olivier Soppera ◽  
Marc Lepeltier ◽  
...  

A new iridium complex (nIr) was designed and investigated as a photoinitiator catalyst for radical and cationic polymerizations upon very soft irradiation.


1974 ◽  
Vol 22 ◽  
pp. 193-203
Author(s):  
L̆ubor Kresák

AbstractStructural effects of the resonance with the mean motion of Jupiter on the system of short-period comets are discussed. The distribution of mean motions, determined from sets of consecutive perihelion passages of all known periodic comets, reveals a number of gaps associated with low-order resonance; most pronounced are those corresponding to the simplest commensurabilities of 5/2, 2/1, 5/3, 3/2, 1/1 and 1/2. The formation of the gaps is explained by a compound effect of five possible types of behaviour of the comets set into an approximate resonance, ranging from quick passages through the gap to temporary librations avoiding closer approaches to Jupiter. In addition to the comets of almost asteroidal appearance, librating with small amplitudes around the lower resonance ratios (Marsden, 1970b), there is an interesting group of faint diffuse comets librating in characteristic periods of about 200 years, with large amplitudes of about±8% in μ and almost±180° in σ, around the 2/1 resonance gap. This transient type of motion appears to be nearly as frequent as a circulating motion with period of revolution of less than one half that of Jupiter. The temporary members of this group are characteristic not only by their appearance but also by rather peculiar discovery conditions.


1984 ◽  
Vol 11 (1) ◽  
pp. 61-73 ◽  
Author(s):  
S P Carter ◽  
D Haigh ◽  
N R J Neil ◽  
Beverley Smith

Summary Excavations at Howe revealed a complex series of settlements which spanned the whole of the Iron Age period and were preceded by two phases of Neolithic activity. A probable stalled cairn was succeeded by a Maes Howe type chambered tomb which was later followed by enclosed settlements of which only scant remains survived. These settlements were replaced by a roundhouse with earth-house, built into the ruins of the chambered tomb. The roundhouse was surrounded by a contemporary defended settlement. Rebuilding led to the development of a broch structure and village. Partial collapse of tower brought about changes in the settlement, andalthougk some houses were maintained as domestic structures, others were rebuilt as iron-working sheds. The construction of smaller buildings and a later Iron Age or Pictish extended farmstead into rubble collapse accompanied a decline in the size of the settlement. The abandonment of the farmstead marked the end of Howe as a settlement site.


2019 ◽  
Vol 13 (1-2) ◽  
pp. 155-181 ◽  
Author(s):  
Richard Tuffin ◽  
Martin Gibbs

For over half-a-century (1803–54), the Australian colony of Van Diemen's Land (Tasmania), played a key part in Britain's globe-spanning unfree diaspora. Today, a rich built and archaeological landscape, augmented by an exhaustive and relatively intact documentary archive, stand as eloquent markers to this convict legacy. As historical archaeologists, we have spent countless hours querying the physical and documentary residues in a bid to understand how the penological, social and economic imperatives of Britain and the colony shaped the management of convict labour. In particular, our task has centred upon the recovery of individual narratives – of both gaoler and gaoled – from such residues, moving away from a traditional focus on the broader outlines of the convict system. This paper illustrates how spatial history methodological processes have been used to relocate individual historic lives back into the convict industrial landscape of the Tasman Peninsula (Tasmania). Focusing on the male-only penal station of Port Arthur (1830–77), we will illustrate how we have reunited the physicality of past spaces and places, with the lives and labours of those who created and navigated them. Simple methodologies have been used to achieve this, designed with onward applicability in mind. A complex series of documents, convict conduct records, have been mined for spatial markers, allowing events and people to be relocated back into space. Through these processes of linkage and visualisation, we have been encouraged to ask further questions about the management of the unfree labour force and how this came to create the landscape we see today.


2020 ◽  
Author(s):  
Tomislav Rovis ◽  
Benjamin D. Ravetz ◽  
Nicholas E. S. Tay ◽  
Candice Joe ◽  
Melda Sezen-Edmonds ◽  
...  

We describe a new family of catalysts that undergo direct ground state singlet to excited state triplet excitation with IR light, leading to photoredox catalysis without the energy waste associated with intersystem crossing. The finding allows a mole scale reaction in batch using infrared irradiation.


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